Oil seal ring of synthetic resin having angularly displaced injection point

Abstract

A seal ring having uniform dimensions and uniform composition over the entire length thereof. This is achieved by properly positioning the injection point for injecting a material when injection-molding the seal ring. More specifically, the injection point is angularly displaced from the center of the entire length of the seal ring by ±1° to ±30°.

What is claimed is: 
     
       1. An oil seal ring of a synthetic resin having two separate, opposite ends and formed by injection-molding a synthetic resin, said seal ring having an injection point for injecting a material located at a position angularly displaced by ±1° to ±30° from the center of the entire length of said seal ring. 
     
     
       2. An oil seal ring as claimed in claim 1 wherein said injection point is located at a position angularly displaced by ±3° to ±30° from the center of the entire length of said seal ring. 
     
     
       3. An oil seal ring as claimed in claim 1 wherein said injection point is located at a position angularly displaced by ±10° to ±30° from the center of the entire length of said seal ring.